Battle for relevance likely to be a fight to the death
For Prime Minister Junichiro Koizumi, Sunday's general election is all about moulding the Liberal Democratic Party into a stable, modern organisation.
For several of the other parties entering the final straight of the campaign, it is about their very existence.
Ever since Mr Koizumi called the election on August 8, the focus has been on rebels who voted against his postal-privatisation bill, 'assassins' hand-picked to storm their electoral strongholds and candidates selected for their television appeal rather than policies.
If even the largest opposition party, the Democratic Party of Japan, throws up its hands in despair at the failure to discuss substance, what chance do the smallest parties have?
'The minor parties are playing diminished parts in Japanese politics, and we're clearly moving to a two-party system,' said Go Ito, a professor of political science at Tokyo's Meiji University.
'It would not surprise me at all if one of them had disappeared entirely by Monday.'
The most likely candidate for demise, he believes, is the Social Democratic Party, which has fallen from grace with a thump.
The SDP took advantage of internal rows in the LDP in the late 1980s and was even briefly the senior party in a coalition with its long-time foe, making Tomiichi Murayama Japan's first socialist prime minister in 47 years.
In the 1990 election, the SDP won a respectable 136 of the 480 seats in the lower house. Today, it has five.
'The party is on the verge of disappearing because it sticks to the very old-fashioned policy of promoting peace instead of war,' said Professor Ito. 'It's the rhetoric of the cold war era.
'Of course people want peace, but the general public does feel that committing peacekeeping troops to hot spots is contributing to world peace,' he said.
'But in reality, social-welfare issues such as pensions, health care and education are more important, and the SDP is neglecting them.'
Japanese politics is notoriously fluid, with politicians frequently changing sides and parties sometimes subverting long-held and fundamental tenets simply to get a foot in a coalition government, but that option is unlikely to be open to Social Democratic Party leader Mizuho Fukushima.
'It would be very difficult for the party to co-operate with anyone else because of their outdated policies, but also because there is historic hostility with the one party they might link up with, the Japanese Communist Party,' Professor Ito said.
The JCP has nine seats in the lower house, with Kazuo Shii, chairman of the party's executive committee, setting the modest target of winning an additional two seats on Sunday.
'In the last two years, there have been many young people approaching us with concerns about two main issues,' said Mr Shii, 54. 'A movement demanding secure jobs for young people has grown up, as well as opposition to the war in Iraq and fears that ... the war- renouncing constitution will be altered.'
Professor Ito said: 'The Communists have shown more flexibility than the SDP in this election.'
And while to some the very presence of a communist party in a nation as steadfastly capitalist as Japan is confusing, Professor Ito says its traditional support bases of the intelligentsia and workers will ensure it survives this election as well.
The two new parties set up by renegades from the LDP - the People's New Party and New Party Nippon - are temporary flags of convenience that are almost certain to wither in the aftermath of the election, their members either defeated or forced to return to one of the more mainstream parties.
That would leave New Komeito as the only party that might have a serious say in where power lies come September 12.
A staunch coalition ally of the LDP, the party draws its support from the lay Buddhist organisation Soka Gakkai. The 34 seats it held going into the election guaranteed Mr Koizumi's majority.
The parties have had their differences, however, most notably over LDP members visiting the Yasukuni Shrine, but Takenori Kanzaki, New Komeito's chief representative, believes the coalition will remain intact even if the LDP wins a simple majority in the election.
The suspicion remains, however, that New Komeito will need the LDP more than vice versa once the results are all in.